# Investigating the Role of Hypoxic Signaling on Adipose-Derived Stem Cell Osteogenesis

> **NIH NIH F31** · JOHNS HOPKINS UNIVERSITY · 2020 · $46,520

## Abstract

Project Summary/Abstract: Craniofacial bone grafts are used to treat over 200,000 patients in the United
States annually. Autograft, the current standard of treatment, has multiple drawbacks including donor-site
morbidity and lack of available tissue. A promising alternative is the combination adipose-derived stem/stromal
cells (ASCs) with osteoinductive biomaterial scaffolds that can be 3D-printed to mimic the native geometry of
the defect. ASCs can be readily obtained in high yields from non-invasive procedures and have been shown to
mineralize robustly in vitro, leading to their utility as a stem cell source. Despite these promising
characteristics, ASCs have demonstrated limited ability to regenerate bone in vivo. A predominant hypothesis
is that the hypoxic environment following implantation may lead to massive cell death; however, in preliminary
in vitro experiments, I have observed excellent (>70%) ASC survival in severely hypoxic culture, but during in
vitro osteogenic differentiation, Runx2 expression and alkaline phosphatase (ALP) activity, two common
markers for osteogenesis, are inhibited by hypoxia. Additionally, through the use of a novel strategy for
delivering oxygen to cells seeded in 3D scaffolds, I have demonstrated that providing oxygen in situ to
transplanted ASCs doubled the amount of bone formed in vivo in a murine ectopic bone formation model.
Thus, the major premise of this proposal is that the reduced in vivo bone formation by ASCs is due to the
direct inhibition of ASC osteogenesis by hypoxia.
 The objective of the proposed study is to investigate the interplay between hypoxia and ASC
osteogenesis, overcoming several major limitations in the field. First, ASC osteogenesis in hypoxia will be
studied quantitatively using a 3D in vitro model of bone formation Previous literature examining the impact of
oxygen on ASC differentiation produced conflicting results, because they relied on qualitative metrics of
osteogenesis. In Specific Aim 1, I will use a 3D in vitro model of bone formation to quantify changes in
mineralization, tissue microarchitecture, metabolism, and gene expression due to hypoxia. Extensive gene
expression data may allow us to identify novel mediators of oxygen-dependent ASC osteogenesis. Next, in
Specific Aim 2, I will investigate the interplay between hypoxic signaling and ASC osteogenesis using gain-of-
function and loss-of-function studies using novel non-viral polymeric nanoparticles and oxygen-releasing
scaffolds. First, I will determine whether the effect of hypoxia on ASC osteogenesis can be simulated by
upregulating hypoxia-inducible factor-1α (HIF-1α) downregulating HIF-1α. Third, I will determine the effect of
oxygen release on ASC osteogenesis. Finally, in Specific Aim 3, I will study the effects of HIF-1α gain-of-
function and loss-of-function and oxygen delivery on ASC osteogenesis in a calvarial defect model. The results
of these studies will deepen the understanding between hypoxia and oste...

## Key facts

- **NIH application ID:** 9910771
- **Project number:** 1F31AR075368-01A1
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Ashley Farris
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $46,520
- **Award type:** 1
- **Project period:** 2020-05-01 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9910771

## Citation

> US National Institutes of Health, RePORTER application 9910771, Investigating the Role of Hypoxic Signaling on Adipose-Derived Stem Cell Osteogenesis (1F31AR075368-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9910771. Licensed CC0.

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